The broad objectives are geared to an appreciation of the integrant aspects of metabolism. Aromatic metabolites link pathways of biosynthesis, catabolism, and secondary metabolism (pyocyanine pigment and related phenazine compounds) in Pseudomonas aeruginosa. The biosynthesis of aromatic amino acids includes some previously undescribed enzymatic sequences that involve an amino acid intermediate denoted pretyrosine. Rigorous techniques of biochemical genetics will be used to establish comprehensive experimental systems in each of the three metabolic sequences, sequences whose physiological roles are vastly divergent. Gene-enzyme relationships and regulatory interplay between these pathways will be the focal point with the overall objective of understanding each metabolic system in the context of the others.